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    <title>Document</title>
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<body>
    <script>
        const p1 = () => {
            return new Promise((resolve, reject) => {
                setTimeout(() => {
                    console.log('p1');
                    resolve('1')
                }, 1000)
            })
        }
        const p2 = () => {
            return new Promise((resolve, reject) => {
                setTimeout(() => {
                    console.log('p2');
                    resolve('2')
                }, 500)
            })
        }
        const p3 = () => {
            return new Promise((resolve, reject) => {
                setTimeout(() => {
                    console.log('p3');
                    resolve('3')
                }, 1500)
            })
        }


        async function fn() {
            const res1 = await p1()
            console.log('res1', res1);
            let a = 2
            if (a > 3) {
                const res2 = await p2()
                console.log('res2', res2);
            } else {
                const res3 = await p3()
                console.log('res3', res3);
            }


        }

        fn().catch(err => {
            console.log(err);
        })
    </script>
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